Exercise of jaw muscles is an important part of treatment and rehabilitation for many jaw injuries and disorders. For example, the common practice of wiring jaws closed as a splinting approach to fractures and bone surgical procedures leads to a shortening of the muscles that close the jaw and a weakening of the muscles that open it. As a result, patients may find it impossible to open their mouths after the wiring has been removed. Physicians and surgeons resort to expedients which include prying with tongue depressors and the use of screw operated wedge devices to stretch the muscles and thereby accomplish opening of the mouth. Once the jaws are opened, it is necessary for patients to undertake exercises to stretch the muscles in order to regain full freedom of motion. Passive elastic devices have been suggested for accompmlishing jaw exercising. Also, expensive spring operated instruments have been developed for this purpose.
A typical defect of most commercially available jaw exercising devices is that they either cause pain and injury through the exertion of excessive force or they may apply pressure to the molar region in a vertical manner thus displacing the condyles downward and disrupting the tempero-mandibular joint. None of these devices moves the lower jaw in a fashion which takes into account the structural features of the jaw hinge, namely that the pivotal point of the jaw hinge is above and to the rear of the mouth opening by virtue of the curvature of the jaw at its upper rear portion.
It is a principal feature, therefore, to provide a novel jaw exercising mechanism which accomplishes movement of the jaw by applying pressure to the teeth along the natural anatomical lines taking account of the natural angles of motion of the mandible.
It is also a feature of this invention to provide a novel passive jaw exercising device that avoids injury by allowing the patient to continuously meter the force that is applied to accomplish opening movement of the jaw.
It is an even further feature of this invention to provide a novel passive jaw exercising device that adjusts for both jaw size and for range of motion and provides for graded application of force for both opening and closing motions.
It is another feature of this invention to provide a novel passive jaw exercising mechanism that utilizes a hand grip designed to take advantage of the natural strength and endurance of the patient's first and second fingers and the patient's hand in general to provide both opening force and closing resistance to the jaw and thereby accomplishes exercising of the muscles that open and close the jaw.
It is a further feature of this invention to provide a novel passive jaw exercising mechanism that can be made inexpensively as a plastic molding for use by a single patient thus insuring against cross contamination between patients and providing for infection control.
It is also a feature of this invention to provide a novel passive jaw exerciser that is adaptable for use by a wide range of patient's having different size jaws through the use of different sized jaw pieces and/or jaw piece extensions.
It is an even further feature of this invention to provide a novel passive jaw exerciser that is capable of providing a motion that is beneficial in facial orthopedics through employment of a motion controlling track of a particular configuration.